This relates generally to electronic devices, and more particularly, to electronic devices with displays.
Electronic devices often include displays. For example, cellular telephones and portable computers often include organic light-emitting diode displays for presenting visual information to a user.
To ensure that organic light-emitting diode displays do not consume too much power, electronic devices often use a peak luminance control algorithm (sometimes referred to as automatic current limiting). When this functionality is enabled, the peak luminance of displayed images is limited whenever the content being displayed exhibits large values of average luminance. When the average luminance of a frame of image data is low, the display is allowed to display content with a large peak luminance. In this situation, a display with sparse content such as a few icons on a black background can display the content brightly.
When the average luminance of a frame of image data is high, there is a potential for excessive current draw by the display if all of the content in the frame is displayed at maximum luminance. When the peak luminance control algorithm is used, the peak luminance of the content is reduced automatically by the display. This ensures that the amount of current and therefore the amount of power that is drawn by the display will be capped. In addition to limiting power consumption, this may help limit temperature rise in the display and thereby help extend the lifetime of display pixels in the display.
Manually and automatically controlled display brightness settings also are used to adjust how brightly organic light-emitting diode displays operate.
Organic light-emitting diode displays produce light by applying current to emissive organic materials. The performance of the emissive organic material in the display pixels of an organic light-emitting diode display can be adversely affected by operation at high currents and temperatures. As a result, organic light-emitting diode displays can be susceptible to burn-in effects in which static content creates undesirable visible artifacts on a display. For example, if a bright menu button is displayed for too long in a fixed location on a display, a faint outline of the menu button may remain visible even when a different image is being displayed on the display.
Although peak luminance control algorithms and global display brightness adjustments can limit excessive display currents, there is still a potential for burn-in effects when bright static content is displayed for too long on a display, particularly at elevated operating temperatures.
It would therefore be desirable to be able to reduce burn-in effects due to displaying static image content.